On/off solenoid expansion device

Abstract

A refrigerant flow-control valve operable between a no-flow condition and a flow condition in response to a control signal supplied thereto. The flow-control valve includes a tubular-shaped body forming a refrigerant passageway extending from an inlet to an outlet, a cylindrically-shaped restrictor secured within the tube and forming a restriction, and a cylindrically-shaped stop secured within the tube and forming a plunger valve flow passage. The stop is located downstream and spaced-apart from the restrictor and the restriction has a greater resistance to flow than the valve flow passage. A plunger is within the tube between the restrictor and the stop and carries a valve element. The plunger is movable between a first position closing the valve flow passage to generally prevent refrigerant flow therethrough and through the passageway and a second position opening the valve flow passage to permit refrigerant flow therethrough and through the passageway. A compression spring is within the tube between the restrictor and the plunger and resiliently urging the valve element into the first position. A solenoid coil located about the tube adjacent the plunger is adapted to selectively move the valve element to the second position in response to a control signal supplied thereto.

What is claimed is:  
     
       1. A refrigerant flow-control valve operable between a no-flow condition and a flow condition, said valve comprising: 
       a body having an inlet and an outlet and forming a refrigerant passageway extending from said inlet to said outlet, said passageway having a restriction and a valve flow passage adapted such that refrigerant flows through said valve flow passage and said restriction generally in series, said restriction located upstream from said valve flow passage;  
       a restrictor located within the passageway of the body and forming the restriction, said restriction axially extending entirely through the restrictor and generally coaxial with the passageway, said restrictor being separate from the body and secured to the body to prevent movement relative to the body, said restrictor having an outer surface sealingly engaging the body to prevent refrigerant flow therebetween;  
       a stop located entirely within the passageway of the body and forming the valve flow passage, said stop being spaced apart and downstream from the restrictor, said stop being separate from the body and secured to the body to prevent movement relative to the body, said stop having an outer surface sealingly engaging the body to prevent refrigerant flow therebetween;  
       wherein said refrigerant passage has a generally constant diameter from an inlet of the restrictor to an outlet of the stop;  
       a valve element within said body and movable between a first position closing said valve flow passage to generally prevent refrigerant flow therethrough and through said passageway and a second position opening said valve flow passage to permit refrigerant flow therethrough and through said passageway;  
       a plunger carrying said valve element and movable between said restrictor and said stop;  
       a biasing member within said body and resiliently urging said valve element into said first position; and  
       a valve actuator adapted to selectively move said valve element to said second position in response to a control signal supplied thereto.  
     
     
       2. A refrigerant flow-control valve according to  claim 1 , wherein said restriction is adapted to have a higher resistance to refrigerant flow than said valve flow passage. 
     
     
       3. A refrigerant flow-control valve according to  claim 1 , wherein said biasing member is compression spring. 
     
     
       4. A refrigerant flow-control valve according to  claim 1 , wherein said valve actuator is a solenoid coil. 
     
     
       5. A refrigerant flow-control valve according to  claim 1 , wherein said valve element is formed by a frusto-conically-shaped protrusion extending from a downstream end of said plunger. 
     
     
       6. A refrigerant flow-control valve according to  claim 1 , wherein an outer periphery of said plunger is adapted for passage of refrigerant past said plunger along said outer periphery. 
     
     
       7. A refrigerant flow-control valve according to  claim 1 , wherein said biasing member is a compression spring having one end seated against said restrictor and another end seated against said plunger. 
     
     
       8. A refrigerant flow-control valve according to  claim 1 , wherein said passageway is generally circular in cross-section, said plunger has a generally cylindrically-shaped bearing surface adapted to cooperate with said passageway, and said bearing surface is adapted to form a flow path to permit refrigerant past the plunger. 
     
     
       9. A refrigerant flow-control valve according to  claim 8 , wherein said flow path is formed by a plurality of axially extending and circumferentially spaced apart channels formed in said bearing surface. 
     
     
       10. A refrigerant flow-control valve according to  claim 1 , wherein said body is a generally straight tube with said inlet at one end and said outlet at an opposite end. 
     
     
       11. A refrigerant flow-control valve according to  claim 1 , wherein said body is a generally straight tube with said inlet at one end and said outlet at an opposite end, said restrictor is cylindrically-shaped, said stop is cylindrically-shaped, and said tube has a constant diameter from the inlet end of the restrictor to the outlet end of the stop. 
     
     
       12. A refrigerant flow-control valve according to  claim 4 , wherein said solenoid coil is secured about the body adjacent the restrictor and the plunger and longitudinally spaced from the stop. 
     
     
       13. A refrigerant flow-control valve according to  claim 12 , wherein a length of the restrictor is generally equal to a length of the plunger. 
     
     
       14. A refrigerant flow-control valve according to  claim 4 , wherein said restrictor extends to a longitudinal center of the solenoid coil. 
     
     
       15. A refrigerant flow-control valve operable between a no-flow condition and a flow condition, said valve comprising: 
       a tube having an inlet and an outlet and forming a refrigerant passageway extending from said inlet to said outlet;  
       a cylindrically-shaped restrictor separate of said tube and secured within said tube to prevent movement relative to the tube, said restrictor forming a restriction axially extending entirely through the restrictor and generally coaxial with the passageway, said restrictor having an outer surface sealingly engaging the tube to prevent refrigerant flow therebetween;  
       a cylindrically-shaped stop separate from the tube and secured within said tube to prevent movement relative to the tube, said stop forming a valve flow passage, said stop being downstream and spaced-apart from said restrictor; said restriction having a greater resistance to flow than said valve flow passage, said stop having an outer surface sealingly engaging the tube to prevent refrigerant flow therebetween;  
       wherein said tube has a constant diameter from an inlet end of the restrictor to an outlet end of the stop;  
       a plunger within said tube between said restrictor and said stop and carrying a valve element, said plunger movable between a first position closing said valve flow passage to generally prevent refrigerant flow therethrough and through said passageway and a second position opening said valve flow passage to permit refrigerant flow therethrough and through said passageway;  
       a biasing member within said tube and resiliently urging said valve element into said first position; and  
       a valve actuator adapted to selectively move said valve element to said second position in response to a control signal supplied thereto.  
     
     
       16. A refrigerant flow-control valve according to  claim 15 , wherein said biasing member is compression spring located within said tube and having one end seated against said restrictor and another end seated against said plunger. 
     
     
       17. A refrigerant flow-control valve according to  claim 15 , wherein said valve actuator includes a solenoid coil located about said tube adjacent said plunger. 
     
     
       18. A refrigerant flow-control valve according to  claim 15 , wherein an outer periphery of said plunger is adapted for passage of refrigerant between said tube and said outer periphery. 
     
     
       19. A refrigeration system having a compressor, a condenser, and an evaporator connected in series and an expansion valve connected in series between the condenser and the evaporator, said refrigeration system comprising: 
       a body having an inlet and an outlet and forming a refrigerant passageway extending from said inlet to said outlet, said passageway having a restriction and a valve flow passage adapted such that refrigerant flows through said valve flow passage and said restriction generally in series, said restriction located upstream from said valve flow passage;  
       a restrictor located within the passageway of the body and forming the restriction, said restriction axially extending entirely through the restrictor and generally coaxial with the passageway, said restrictor being separate from the body and secured to the body to prevent movement relative to the body, said restrictor having an outer surface sealingly engaging the body to prevent refrigerant flow therebetween;  
       a stop located entirely within the passageway of the body and forming the valve flow passage, said stop being spaced apart and downstream from the restrictor, said stop being separate from the body and secured to the body to prevent movement relative to the body, said stop having an outer surface sealingly engaging the body to prevent refrigerant flow therebetween;  
       wherein said refrigerant passage has a generally constant diameter from an inlet of the restrictor to an outlet of the stop;  
       a valve element within said body and movable between a first position closing said valve flow passage to generally prevent refrigerant flow therethrough and through said passageway and a second position opening said valve flow passage to permit refrigerant flow therethrough and through said passageway;  
       a plunger carrying said valve element and movable between said restrictor and said stop;  
       a biasing member within said body and resiliently urging said valve element into said first position; and  
       a valve actuator adapted to selectively move said valve element to said second position in response to a control signal supplied thereto.  
     
     
       20. A refrigerant flow-control valve according to  claim 19 , wherein said valve actuator is a solenoid coil and said solenoid coil is secured about the body adjacent the restrictor and the plunger and longitudinally spaced from the stop. 
     
     
       21. A refrigerant flow-control valve according to  claim 20 , wherein a length of the restrictor is generally equal to a length of the plunger. 
     
     
       22. A refrigerant flow-control valve according to  claim 19 , wherein said valve actuator is a solenoid coil and said restrictor extends to a longitudinal center of the solenoid coil. 
     
     
       23. A method of delivering refrigerant from a high pressure region to a low pressure region of a refrigeration system through a variable dimension passageway to expand the refrigerant as it enters the low pressure region, said method comprising the steps of: 
       (a) coupling the high and low pressure regions through a valve body having an inlet and an outlet and forming a refrigerant passageway extending from the inlet to the outlet, the passageway having a restriction and a valve flow passage downstream of the restriction and adapted such that refrigerant flows through the valve flow passage generally in series with the restriction;  
       (b) mounting a restrictor, separate from the body, within the passageway of the body to form the restriction such that the restrictor is secured to the body to prevent movement relative to the body and the restrictor sealingly engages the body to prevent refrigerant flow therebetween;  
       (c) providing a restriction which axially extends entirely through the restrictor and generally coaxial with the passageway;  
       (d) mounting a stop, separate from the body, within the passageway to form the valve such that the stop is spaced apart and downstream from the restrictor, secured to the body to prevent movement relative to the body, and sealingly engaging the body to prevent refrigerant flow therebetween;  
       (e) providing the refrigerant passage with a generally constant diameter from an inlet of the restrictor to an outlet of the stop;  
       (f) mounting a valve element within the valve body such that the valve element is movable between a first position closing the valve flow passage to generally prevent refrigerant flow therethrough and through the passageway and a second position opening the valve flow passage to permit refrigerant flow therethrough and through the passageway;  
       (g) biasing the valve element into the first position; and  
       (h) selectively moving the valve element to the second position with a valve actuator in response to a control signal supplied to the valve actuator.